My toolbag calipers are cheap hardware store ones. They’re accurate enough and I’m not out much when they inevitably get damaged or lost.

For a machinist yep. For home gamers, a waste of money. They don’t have the knowledge of where and when to use them nor the skills to get accurate repeatable measurements. So for OP’s use whatever CCC, (Cheap, Cheerful, Chinese), caliper he’s got is good enough.

It’s the definition of “nominal size is what ever we say it is” that pisses me off. Buying wood/lumber is the worst offender of Nominal sizing, but even metals are getting worse. I used to buy a round bar of say, ASA1018 and it would be +0"/-.002". It’s now +0/-.006", (that’s +0/-.05mm and +0/-.15mm for those living in Boca Raton). At the end of my career as a toolmaker I was often forced to purchase oversized stock and waste time turning said stock into the actual sizes required.

I can accept the poor quality tools that might be off by a few hundredths, but using imperial on precision measurement devices is unforgivable.